Modern vehicles typically have one or more diagnostic systems, generally having separate computer control modules, such as an electronic control unit (ECU) to control various functions of the vehicle. Some examples include a powertrain control module (PCM), an engine control module (ECM), a transmission control module (TCM), an anti-locking brake system (ABS), and supplemental restraint system module (SRS). The vehicle diagnostic systems, such OBD II has self-diagnostic capabilities to detect and alert the driver of problems that the vehicle may be encountering. When a problem is detected, a diagnostic trouble code (DTC) is set within the module's memory. DTCs are as general or as specific as the manufacturer desires.
To retrieve and decipher DTCs, an auto repair technician needs a diagnostic tool, such as a scan tool. The diagnostic tool is connected to the OBD II (On-Board Diagnostic) via a data link connector (DLC) to access and retrieve the DTCs. Diagnostic tools are equipped to communicate in various communication protocols used in the vehicle such as Controller Area Network (CAN), J1850 VPM and PWM, ISO 9141, Keyword 2000 and others. These communication protocols may be specific to each of the various vehicle manufacturers. The diagnostic tool will help the technician to diagnose and repair the vehicle based on the information the tool retrieves from the vehicle.
The diagnostic tools have limited and dated diagnostic information in their database stored on the diagnostic tool. Accordingly, it is desirable to provide a method and apparatus that allow a diagnostic tool to have the most up to date diagnostic information available in order to provide accurate diagnoses of the vehicle.